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The microbial quality of livestock drinking water was evaluated in 473 cattle water troughs located at 99 different cattle operations. The mean log10-transformed coliform and Escherichia coli concentrations per milliliter of trough water were 1.76 +/- 1.25 (SD) and 0.98 +/- 1.06 (SD), respectively. The degree of E. coli contamination was positively associated with the proximity of the water trough to the feedbunk, protection of the trough from direct sunlight, lower concentrations of protozoa in the water, and warmer weather. Salmonella sp. were isolated from 2/235 (0.8%) troughs and shigatoxigenic-E. coli O157 was recovered from 6/473 (1.3%) troughs. Four experimental microcosms simulating cattle water troughs were used to further evaluate the effects of protozoal populations on the survival of E. coli O157 in cattle water troughs. Escherichia coli O157 of bovine fecal origin proliferated in all microcosms. Reduction of protozoal populations by treatment with cycloheximide was associated with increased persistence of E. coli O157 concentrations in the microcosms. Water troughs are a major source of exposure of cattle to enteric bacteria, including a number of foodborne pathogens, and this degree of bacterial contamination appeared to be associated with potentially controllable factors.

Antibiotic resistance, particularly to fluoroquinolones and macrolides, in the major foodborne pathogen Campylobacter is considered a serious threat to public health. Although ruminant animals serve as a significant reservoir for Campylobacter, limited information is available on antibiotic-resistant Campylobacter of bovine origin. Here, we analyzed the antimicrobial susceptibilities of 320 C. jejuni and 115 C. coli isolates obtained from feedlot cattle farms in multiple states in the U.S. The results indicate that fluoroquinolone resistance reached to 35.4% in C. jejuni and 74.4% in C. coli, which are significantly higher than those previously reported in the U.S. While all fluoroquinolone resistant (FQR) C. coli isolates examined in this study harbored the single Thr-86-Ile mutation in GyrA, FQR C. jejuni isolates had other mutations in GyrA in addition to the Thr-86-Ile change. Notably, most of the analyzed FQR C. coli isolates had similar PFGE (pulsed field gel electrophoresis) patterns and the same MLST (multilocus sequence typing) sequence type (ST-1068) regardless of their geographic sources and time of isolation, while the analyzed C. jejuni isolates were genetically diverse, suggesting that clonal expansion is involved in dissemination of FQR C. coli but not C. jejuni. These findings reveal the rising prevalence of FQR Campylobacter in the U.S. and provide novel information on the epidemiology of antibiotic-resistant Campylobacter in the ruminant reservoir.

Experts have long sought to understand the factors that underlie farmer decision making for weed management. The majority of this interest has been in relation to the weak adoption of integrated management approaches and more recently, herbicide resistance strategies. In order to increase adoption in these contexts there is a need to understand better the underlying drivers for weed management decisions. The objective of the research reported here was to probe farmers' understanding of weed management to establish a baseline understanding of these key drivers. Thirty Ohio farmers participated in an in-depth interview where they were asked to reflect on how weeds are introduced and spread, what risks and benefits weeds pose, and what management strategies farmers are familiar with and which they prefer. Their responses were mapped, coded, and analyzed for dominant beliefs and major decision-making influences. The results indicate that farmers largely attribute the introduction and movement of weeds to factors outside their control (e.g., the environment, plant characteristics). They frequently cite diverse and integrated management, but their focus is on control as opposed to prevention. In general, they tend to receive messages about integrated and preventive approaches, but do not always put them into practice because of underlying beliefs about the inevitability of new weed introductions and spread.